Presentation on theme: "1.Combination of atoms to form a compound (with different properties) 2. Determined by electrons in atoms 3. Why bond? To increase stability To."— Presentation transcript:
1.Combination of atoms to form a compound (with different properties) 2. Determined by electrons in atoms 3. Why bond? To increase stability To decrease energy To fill valence!! 4. A balanced combination of positive and negative ions. 5. Simplest whole number ratio
Chemical compounds form so that each element has a full octet of electrons in its highest energy level. This can happen through gaining, losing, or sharing electrons.
Review Unit 5 Tests Redo policy Before Thanksgiving Break? Review Ionic Compounds Properties Continue Puzzle Piece activity Let’s Clarify the directions HW: Finish analysis questions for Activity
Ionic Bond The chemical bond resulting from electrostatic attraction between positive and negative ions. Metals tend to lose electrons and form cations. Nonmetals tend to gain electrons and form anions
Solid state is a crystalline structure Hard, brittle solids High melting point NaCl is 801 o C Do not conduct electricity as solids Do conduct as liquids and solutions Not discreet molecules, instead called formula units
Identify charges of both the cation and the anion. Collect puzzle pieces that correspond to the ions. Adding more of only those charges, continue adding pieces until you have a complete and stable compound. Puzzle Method
Each pair needs new puzzle pieces The goal of fitting the pieces together is to make a complete rectangle or square. Cations can only bond with anions!! Your job is to make 20 combinations Do Not try the Naming Yet!!!
Finish Formula Writing Lab Homework for tomorrow Go Over Unit 5 Test Collect Formula Writing Lab (3 and 8) 1 per group Notes on writing and naming Ionic Compounds
Meet with your lab partners Compare answers to analysis questions, and your conclusions. Determine which of the two labs you will turn in. Both partners names should be on the lab.
Get into your white board groups One marker per group
Write the correct formula for the following cation and anion pairs: 1. Na + and Cl - 2. Mg +2 and F - 3. C -4 and H + 4. Ag +3 and O Ag +3 and N -3 Bonus Question: Is there a pattern you notice between the charges on the ions and the subscripts in the formulas?
Identify charges of both the cation and the anion. Switch the charge value to be the opposite ion’s newest subscript. Repeat for the other ion. Example: Ag +3 O -2 Ag 2 O 3
Ag +3 and N -3 Do the criss-cross method If the subscripts can be reduced…reduce them!
Cation is always named first Cation take the name of the element Transition metals use the formula to find the charge (Roman numeral = charge) Anion Monatomic (only one element) end in –ide
CaF 2 calcium fluoride Li 2 S Lithium sulfide FeCl 2 (This is a transition metal) Iron (II) chloride (ferrous chloride) FeCl 3 (This is a transition metal) Iron (III) chloride (ferric chloride)
PtO 2 Platinum (IV) oxide CuBr Copper (I) bromide (cuprous bromide) Zn 3 N 2 Zinc (II) nitride (Zn is almost always +2) Sn 3 P 2 Tin (II) phosphide (stannous phosphide)
Review Ionic Formula Writing Notes on Polyatomic Ions Naming Notes on naming Covalent Compounds Properties of covalent compounds HW: Naming monatomic and polyatomic formulas
Bonds that exist between two non-metals Two anions!! Both atoms want to gain electrons so they share electrons in bonds to complete their octet.
These exist between two different anions. Ex: Carbon monoxide, CO, C==O Many different solid forms, not crystalline Relatively low melting and boiling point. Poor conductors in all states! Do not dissolve in water very well. Organic compounds are examples of molecular substances.
Bonds between one non-metal element Ex: C 60 Buckminsterfullerene Buckyballs Diamond, Graphite, and Carbon nanotubes
Different shapes in the solid form. High melting and boiling points Often hard and brittle Non-conducting solids Do not dissolve in water well
1. First element using full element name 2. Second element name as if it were an anion (-ide) 3. Use prefixes to denote # of atoms present for both of the elements - exception: mono is NOT used for the first element. Ex: CO Carbon monoxide Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
One mono- Two di- Three tri- Four tetra- Five penta- Six hexa- Seven hepta- Eight octa- Nine nona- Ten deca-
Review all types of naming Notes on metallic substances Practice Practice Practice HW: Naming covalent compounds
1. S 2 F 3 4. PbO 2 2. BeS5. LiOH 3. CO 2 6. NCl 3
Metallic bonds are described as a cluster of positive metal ions surrounded by a sea of their shared valence electrons. Metallic Bonding is the type of bonding found in metallic substances. The positive ions remain fixed in a crystal lattice, while the loosely-held valence electrons move freely throughout the entire crystal. Melting/boiling points between covalent and ionic compounds. Not soluble in water.
Insert figure 8.9 A Model of Metallic Bonding The positive metal ions are surrounded by a huge cloud of free flowing electrons.
Metals are great conductors of electricity. Why? Electricity can be described as a movement of charged particles, so if you have mobile charged particles present then electricity can flow. For metals, the sea of electrons is basically a cloud of mobile charged particles.
Malleable: Can be beaten into a thin sheet Ductile: Can be pulled into a wire. Why? If you add stress you force like charges closer together. They repel each other and move apart, but instead of shattering, the particles rearrange with the sea of electrons.
Metals are shiny!! Why? The valence electrons move within the “sea” around the positive ions of the metals. When the light wave hits the electrons in the “sea”, the light “bounces” off of them or is reflected back by the electrons. When this light hits our eyes, the appearance we see is that the metal is shiny.